[PATCH] D135876: [VectorCombine] Scalarize binops with insertelt nested inside splats

[Matt Devereau via Phabricator via llvm-commits]

MattDevereau created this revision.
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where a, b are scalar values, VectorCombine:

  shufflevector(vector binop (shufflevector(insertelt(undef, a, 0),
                                                                         undef,
                                                                         zeroinitializer),
                                                 insertelt(undef, b, 0)),
                          undef,
                          zeroinitializer)

to

  shufflevector(insertelt(undef, binop (a, b), 0), undef, zeroinitializer)
   

This elimates series of unnecessary vectorized shufflevectors and insertelements
which can result in pointless vectorized bin ops later on, and replaces them
with scalar binops.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D135876

Files:
  llvm/lib/Transforms/Vectorize/VectorCombine.cpp
  llvm/test/Transforms/VectorCombine/AArch64/insert-shuffle-binop.ll

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